Image sensor, image sensor testing system and method

Abstract

The present disclosure relates to an image sensor, an image sensor testing system and a method. The image sensor may include: an active pixel array including a plurality of active pixels operable to convert incident light into a pixel signal carrying image information in the incident light; a plurality of sampling pixel groups located adjacent to the active pixel array but spatially separated from the active pixel array and having heat dissipation characteristics different from other sampling pixel groups; and a plurality of temperature sensors respectively connected to the sampling pixel groups to provide temperature measurements.

Description

Technical Field

[0001] The technologies and implementations disclosed in this patent document generally relate to a semiconductor integrated device, and more specifically, to an image sensor and an image sensor testing system and method. Background Art

[0002] The image sensor includes a pixel array including an optoelectronic semiconductor device and a transistor. The optoelectronic semiconductor device can convert light into photocharges. The transistor can convert the photocharges generated by the optoelectronic semiconductor device into electrical signals.

[0003] A CMOS image sensor may include a single integrated circuit (IC) in which an analog control circuit and a digital control circuit are integrated. A CMOS image sensor may convert light reflected from an object and incident on an optoelectronic semiconductor device of a pixel array into an electric charge. The amount of accumulated charge is proportional to a voltage signal generated by the CMOS image sensor.

[0004] The electrical signals generated by an array of pixels in an image sensor may include noise that may adversely affect the quality of the image.

[0005] Examples of noise include dark current, a relatively small current that flows through a photosensitive device such as a photodiode even when no photons enter the device, which causes distortion of the image signal. Therefore, technology for eliminating noise is being studied. Summary of the invention

[0006] The technology disclosed in this patent document can be implemented in various embodiments to provide an image sensor, which includes: an active pixel array, the active pixel array includes a plurality of active pixels, the active pixels can be operated to convert incident light into pixel signals carrying image information in the incident light; a plurality of sampling pixel groups, the plurality of sampling pixel groups are located adjacent to the active pixel array but spatially separated from the active pixel array, and have different heat dissipation characteristics from other sampling pixel groups; and a plurality of temperature sensors, the plurality of temperature sensors are respectively connected to the sampling pixel groups to provide temperature measurement.

[0007] In an example embodiment of the present disclosure, an image sensor testing system may include: an image sensor, the image sensor including a plurality of sampling pixel groups having heat dissipation characteristics different from other sampling pixel groups and a plurality of temperature sensors respectively connected to the sampling pixel groups to generate temperature detection signals; a temperature detector, the temperature detector respectively receiving temperature detection signals corresponding to the sampling pixel groups from the temperature sensors to determine operating temperature information associated with the sampling pixel groups; and a testing device, the testing device receiving dark current from the sampling pixel groups to determine correction data to be used to correct the dark current, the correction data including a dark level correction value and a base value correction coefficient for each temperature range.

[0008] In an example embodiment of the present disclosure, an image sensor testing method includes the following steps: providing an image sensor including a plurality of sampling pixel groups having different heat dissipation characteristics and a plurality of temperature sensors respectively connected to the sampling pixel groups; providing a testing device to receive operating temperature information including temperatures in the sampling pixel groups in the testing device; receiving a dark current from the sampling pixel groups; and determining correction data to be used to correct the dark current, wherein the correction data includes a dark level correction value and a base correction coefficient for each temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An image sensor testing system based on an example implementation of the disclosed technology is shown.

[0010] Figure 2A and Figure 2B An image sensor testing system based on an example implementation of the disclosed technology is shown.

[0011] Figure 3 A pixel array of an image sensor based on an example implementation of the disclosed technology is shown.

[0012] Figure 4 An active pixel based on an example implementation of the disclosed technology is shown.

[0013] Figure 5 Sample pixels based on an example implementation of the disclosed technology are shown.

[0014] Figure 6 is a flow chart illustrating an image sensor testing method based on an example implementation of the disclosed technology.

[0015] Figure 7 An electronic device based on an example implementation of the disclosed technology is shown.

[0016] Figure 8 An electronic device based on an example implementation of the disclosed technology is shown.

[0017] Fig. 9 An electronic device based on an example implementation of the disclosed technology is shown. DETAILED DESCRIPTION

[0018] Features of the technology disclosed in this patent document are described by referring to examples of image sensing devices of the accompanying drawings.

[0019] Although some implementations of the disclosed technology will be discussed, the disclosed technology may be implemented in a variety of ways beyond the details of the examples described herein.

[0020] Figure 1 An image sensor testing system based on an example implementation of the disclosed technology is shown.

[0021] Reference Figure 1 The image sensor test system 10 may include a device under test (DUT) 110, a test device 130 connected to the DUT 110 to perform a test on the DUT 110, and an interface circuit (IF) 120 connected between the DUT 110 and the test device 130 as an electrical interface for transmitting signals between the DUT 110 and the test device 130.

[0022] The DUT 110 may include at least one image sensor to be tested. In some implementations, the DUT 110 may include different image sensors, while in other implementations, the DUT 110 may include one image sensor. Figure 2A , an image sensor as a part of DUT 110 or DUT 110 may include an active pixel array 115 of active pixels (APXs) for capturing incident light and generating pixel signals carrying an image of the incident light, a plurality of sampling pixel groups, and a plurality of temperature sensors. In some implementations, the active pixel array may include image sensing pixels that convert incident light into pixel signals. The disclosed technology may be implemented in some embodiments to provide an image sensor including a plurality of image sensor pixel groups or a plurality of image sensor pixels having different characteristics, thereby achieving efficient testing of the image sensor. In some implementations, the characteristics of the image sensor pixels or image sensor pixel groups may include heat dissipation characteristics. In one example, at least one of the sampling pixel groups may have a heat dissipation characteristic different from that of the other sampling pixel groups. In another example, the sampling pixel groups have heat dissipation characteristics different from each other. The temperature sensor may be connected to each sampling pixel group, respectively.

[0023] The test system 10 can evaluate the characteristics of the image sensor 110 after the wafer-level process. In addition, the test system 10 can then generate correction data based on the evaluated characteristics. In some implementations, the correction data can include information required to correct or change the design, structure, and manufacturing process of the DUT 110.

[0024] The interface circuit 120 may be electrically connected between the image sensor 110 and the test equipment 130 .

[0025] The test equipment 130 may include a test pattern generator 131 and a correction data generator 133. In some implementations, the test pattern may include a data input pattern or a test signal used to test a semiconductor device after manufacturing or to help determine the cause of a failure.

[0026] The test pattern generator 131 may transmit a test signal to the image sensor 110 through the interface circuit 120. The correction data generator 133 may receive a test response signal corresponding to the test signal of the image sensor 110. The correction data generator 133 may evaluate the characteristics of the image sensor 110 based on the test response signal. The correction data generator 133 may generate correction data based on the evaluated characteristics.

[0027] In some example embodiments of the disclosed technology, the test pattern generator 131 may send a single temperature signal as a test signal to the image sensor 110. The correction data generator 133 may receive a test response signal including a temperature detection signal, an optical black signal, and an active black signal to extract correction data based on temperature. In some implementations, the correction data generator 133 may receive a temperature detection signal, an optical black signal, and an active black signal on the basis of a sampled pixel group to extract correction data on the basis of a sampled pixel group. In some implementations, the active black signal may include a pixel signal generated by an optically black active pixel. The correction data may include a dark level correction value for correcting or removing a dark level of an active pixel array, and a pedestal correction coefficient for preventing clipping of an image signal. In some implementations, the dark level correction value may be used to remove noise associated with a dark current.

[0028] Figure 2A An image sensor testing system based on an example implementation of the disclosed technology is shown.

[0029] Reference Figure 2A, the image sensor test system 10 - 1 may include an image sensor 110 corresponding to the DUT and a test device 130 coupled to the image sensor 110 . The test device 130 may include a test pattern generator 131 and a correction data generator 133 .

[0030] like Figure 2A As shown, the interface circuit 120 on the circuit board (not shown) of the test equipment 130 may be omitted.

[0031] The image sensor 110 may include a pixel array 117 and a temperature sensor 113. The pixel array 117 may include a sampling pixel array 111 and an active pixel array 115. The temperature sensor 113 may be coupled to the sampling pixel array 111. Figures 3 to 5 Discuss pixel array 117 and temperature sensor 113.

[0032] Figure 2B An image sensor testing system based on an example implementation of the disclosed technology is shown.

[0033] Reference Figure 2B , the image sensor test system 10 - 2 may include a package type module including a test device 135 and an image sensor 110 formed of a chip on board (COB) or a plastic lead chip carrier (PLCC).

[0034] The test equipment 135 may include a correction data generator 133 .

[0035] The module-type image sensor test system 10 - 2 may be mounted on an image sensing device. Figure 2B The operating temperature of the image sensor 110 in the apparatus can be determined based on the external temperature when the image sensor is exposed to the outside and the operating state of the ISP in the sensing device. The test equipment 135 can detect the temperature of the apparatus under test based on the operating temperature of the image sensor 110 to determine the dark level correction value and the base correction coefficient.

[0036] In some example embodiments of the disclosed technology, the temperature detector 1331 may form a module together with the image sensor 110. That is, the temperature detector 1331 may be packaged together with the image sensor 110. The dark level correction value determination circuit 1333 and the base correction coefficient determination circuit 1335 may be mounted on the ISP.

[0037] Figure 3 A pixel array of an image sensor based on an example implementation of the disclosed technology is shown.

[0038] Reference Figure 3, the pixel array 117 of the image sensor 110 may include an active region 117A, an optical black region 117B, and a dummy region 117C.

[0039] An active pixel array including a plurality of active pixels APX may be formed in the active region 117A. The active pixels APX may correspond to image sensor pixels configured to respond to incident light and generate active signals carrying image information in the incident light.

[0040] The optical black region 117B may be located outside the active region 117A. In some implementations, the optical black region 117B may be arranged to surround the active region 117A. The optical black region 117B may include an array of optical black pixels OBPX. The optical black pixels OBPX may be used to compensate for dark current. The optical black pixels OBPX may maintain a "black" level by blocking light using a metal barrier layer and a black filter. The optical black pixels OBPX may generate an optical black signal.

[0041] Pixel array 117 may also include additional pixel array regions such as dummy region 117C. Figure 3 As shown in FIG. 1 , in some implementations, the dummy region 117C may be located between the active region 117A and the optical black region 117B. The dummy region 117C may include a plurality of dummy pixels DPX for blocking charges from flowing from the active region 117A into the optical black pixels OBPX of the optical black region 117B.

[0042] A plurality of sampling pixels SPX may be formed in at least one of the optical black region 117B and the dummy region 117C.

[0043] In some example implementations of the disclosed technology, Figure 2A and Figure 2B As shown in , the sampling pixel array 111 may include a plurality of sampling pixel groups G1, G2, ... GN. At least one of the sampling pixel groups G1, G2, ... GN may include a sampling light blocking pixel. In addition, at least one of the sampling pixel groups G1, G2, ... GN may include a sampling active pixel. The sampling pixel groups G1, G2, ... GN may be arranged in Figure 3 The optically black region 117B and / or the dummy region 117C are shown.

[0044] Figure 4 An active pixel based on an example implementation of the disclosed technology is shown. Specifically, Figure 4 It is along Figure 3 A cross-sectional view taken along line AA' in FIG.

[0045] Reference Figure 4, each of the active pixels APX1, APX2, and APX3 may include a grid pattern 310, a transparent layer 320, a color filter 330, and a light collection layer 340 formed over a substrate 300. The substrate 300 may include a photoelectric conversion element PD. The grid pattern 310 may be formed on the substrate 300. The transparent layer 320 may be configured to cover the grid pattern 310. The color filter 330 may be formed on the transparent layer 320. The light collection layer 340 may be formed on the color filter 330. The light collection layer 340 may include a hemispherical microlens.

[0046] The substrate 300 may include a semiconductor substrate. For example, the substrate 300 may include a single crystal silicon substrate.

[0047] Examples of the photoelectric conversion element PD may include an organic or inorganic photodiode, a phototransistor, a photogate, and a combination thereof.

[0048] The grid pattern 310 may prevent optical crosstalk between adjacent active pixels APX. The grid pattern 310 may be formed along the boundary of the photoelectric conversion element PD. The active pixels APX may be arranged in an array so that the grid pattern 310 may have a grid shape when viewed from above.

[0049] The transparent layer 320 may have a flat upper surface to allow an optical signal to pass through the light collecting layer 340 and the color filter 330 to reach the photoelectric conversion element PD.

[0050] The color filter 330 may transmit optical signals within a specific wavelength range.

[0051] The color filter 330 may include a red color filter for a “red” wavelength region, a green color filter for a “green” wavelength region, and a blue color filter for a “blue” wavelength region.

[0052] In some example embodiments of the disclosed technology, the color filter 330 may include at least one of a cyan color filter, a yellow color filter, and a magenta color filter.

[0053] Although not shown in the drawings, an anti-reflection layer may be formed between the light collection layer 340 and the color filter 330 , or between the color filter 330 and the transparent layer 320 , to increase the amount of light transmitted to the photoelectric conversion element PD.

[0054] The photoelectric conversion element PD can output an electrical signal in response to incident light. For example, the photoelectric conversion element PD can generate a charge or current based on the amount of light or light intensity of the optical signal. The output value (active signal of the active pixel APX) can be determined based on the amount of current or charge generated by the photoelectric conversion element PD.

[0055] like Figure 4As shown, in some implementations, the unit active pixel APX may include one photoelectric conversion element PD. In other implementations, the unit active pixel APX may include multiple photoelectric conversion elements.

[0056] Figure 5 Sampled pixels based on an example implementation are shown.

[0057] Figure 5 A first sampling pixel SPX1 (a) in the first sampling pixel group G1 , a second sampling pixel SPX2 (b) in the second sampling pixel group G2 , and a third sampling pixel SPX3 (c) in the third sampling pixel group G3 are shown.

[0058] Each of the sampling pixels SPX1, SPX2, and SPX3 may include a substrate 400, a grid pattern 410, heat dissipation layers 420A, 420B, and 420C, color filters 430A, 430B, and 430C, and a light collection layer 440. The substrate 400 may include a photoelectric conversion element PD. The grid pattern 410 may be formed on the substrate 400. The heat dissipation layers 420A, 420B, and 420C may be configured to cover the grid pattern 410. The color filters 430A, 430B, and 430C may be formed on the heat dissipation layers 420A, 420B, and 420C. The light collection layer 440 may be formed on the color filters 430A, 430B, and 430C. The light collection layer 440 may include a hemispherical microlens.

[0059] The heat dissipation layers 420A, 420B, and 420C of different sampling pixels SPX1, SPX2, and SPX3 in different sampling pixel groups G1, G2, and G3 may have different heights H1, H2, and H3 from the photoelectric conversion element PD. The heat dissipation layers 420A, 420B, and 420C may include a material with low thermal conductivity (e.g., an insulating layer such as a SiO2 layer). In some implementations, the heat dissipation layers 420A, 420B, and 420C may include an air gap.

[0060] In some implementations, each of the heat dissipation layers 420A, 420B, and 420C has a low thermal conductivity, resulting in a low amount of heat dissipation, and the amount of heat dissipation decreases in proportion to an increase in the heights H1, H2, and H3 of the heat dissipation layers 420A, 420B, and 420C. In addition, when the first to third sampling pixels SPX1, SPX2, and SPX3 operate at the same temperature, the amount of heat dissipation is the lowest at the highest dissipation layer.

[0061] The sampling pixels SPX1, SPX2, and SPX3 may be manufactured together with the active pixels APX until the mesh pattern 410 may be formed. The height difference caused by the different heights of the heat dissipation layers 420A, 420B, and 420C may be overcome by controlling the thickness of the color filters 430A, 430B, and 430C.

[0062] like Figure 5 As shown, in some implementations, heat dissipation layers 420A, 420B, and 420C may be disposed below color filters 430A, 430B, and 430C. In other implementations, heat dissipation layers 420A, 420B, and 420C may be located above color filters 430A, 430B, and 430C.

[0063] In order to operate at least one of the sampling pixel groups as a sampling light-shielded pixel and to operate at least one of the sampling pixel groups as a sampling active pixel, the color filters 430A, 430B and 430C of the sampling light-shielded pixels may include shielding materials, and the color filters 430A, 430B and 430C of the sampling active pixels may include light-transmitting materials.

[0064] In some example embodiments of the disclosed technology, the sampling light shielding pixels may be formed in Figure 3 The sampling active pixels may be formed in the optical black region 117B and / or the dummy region 117C. Figure 3 In the active region 117A.

[0065] 2 , the temperature sensor 113 coupled to the sampling pixel array 111 may include a plurality of temperature sensors 1131 , 1132 . . . 113N. In some implementations, the temperature sensors 1131 , 1132 . . . 113N may include bipolar junction transistor (BJT) based temperature sensors.

[0066] like Figure 5 As shown, for example, the sampling pixel groups G1, G2, ..., GN may have different heat dissipation characteristics. Each of the sampling pixel groups G1, G2, ..., GN may include sampling light-shielded pixels and sampling active pixels.

[0067] The test device 130 may include a test pattern generator 131 and a correction data generator 133 .

[0068] During the test, the test pattern generator 131 may apply a single temperature signal TT to the sampling pixel array 111 to heat the sampling pixel array 111. The temperature sensors 1131, 1132, ... 113N may sense the operating temperature of the sampling pixel groups G1, G2, ... GN. In some implementations, the operating temperature may be detected based on the sampling pixel groups. Because the sampling pixel groups G1, G2, ... GN may have different heat dissipation characteristics, the sampling pixel groups G1, G2, ... GN may exhibit different operating temperatures in response to the same temperature signal TT. Therefore, the temperature detection signals corresponding to the sampling pixel groups G1, G2, ... GN output from the temperature sensors 1131, 1132, ... 113N may be different from each other.

[0069] The correction data generator 133 may include a temperature detector 1331 , a dark level correction value determination circuit 1333 , and a base correction coefficient determination circuit 1335 .

[0070] The temperature detector 1331 may receive temperature detection signals DT1, DT2, and DT3 from the temperature sensors 1131, 1132, ..., 113N to respectively detect temperature information associated with the sampling pixel groups G1, G2, ..., GN. In some implementations, the temperature information may include an operating temperature of the sampling pixel group and a temperature in the sampling pixel group.

[0071] During the test, the sampled active pixels of each group may be blocked from light. The dark level correction value determination circuit 1333 may receive the temperature detection signal through the sampled pixel groups G1, G2 ... GN, the optical black signal from the sampled light shielded pixel, and the active black signal from the sampled active pixel as the test response signal. The dark level correction value determination circuit 1333 may determine the dark level correction value for correcting the dark current of the sampled active pixel for each temperature range (e.g., operating temperature, temperature in the sampled pixel group) of the sampled pixel groups G1, G2 ... GN.

[0072] In some implementations, in order to prevent the dark level corrected output signal of the image sensor 110 from being negative, an offset of a specific level may be added to the dark level correction value. The offset used to compensate the dark level correction value may be a base value. Base value correction may prevent clipping of the image signal.

[0073] The base correction coefficient determination circuit 1335 may determine the base correction coefficient to be added to the dark level correction value by the operating temperature.

[0074] The dark level correction value and the base value correction coefficient for the temperature of each sampling pixel group can be obtained by performing calculations. The dark level correction value and the base value correction coefficient at a temperature range outside the detected temperature range can be predicted.

[0075] In some example embodiments of the disclosed technology, the base correction coefficient determination circuit 1335 may calculate the ratio of the active black signal to the optical black signal as the base correction coefficient for each sampled pixel group or according to the operating temperature or the temperature in the pixel. The dark level correction value and the base correction coefficient for each temperature range of the sampled pixel group may be calculated during the test. Based on the calculated dark level correction value and the calculated base correction coefficient, the dark level correction value and the base correction coefficient corresponding to the temperature range outside the detected temperature range may be predicted based on a specific calculation formula.

[0076] The dark level correction value according to the operating temperature determined or predicted by the dark level correction value determination circuit 1333 and the base correction coefficient according to the operating temperature calculated or predicted by the base correction coefficient determination circuit 1335 can be maintained in a lookup table. The lookup table can then be stored in the image sensing device. The disclosed technology can be implemented in some embodiments to provide a processor including hardware and / or software to perform calculations using mathematical formulas to obtain dark level correction values ​​and base correction coefficients based on each temperature.

[0077] In some implementations, when the characteristics of the image sensor can be tested based on the operating temperature, multiple different tests can be performed at various test temperatures. This process of performing different tests for various different test temperatures takes time and may be undesirable.

[0078] In recognition of the limitations of the above-mentioned multiple test process, the disclosed technology can be implemented to include different pixel groups in the sampled pixel array that have different heat dissipation characteristics and exhibit different operating temperatures at a single test temperature. Therefore, by implementing the disclosed technology, a single test at one test temperature can be used to measure different characteristics of different pixels, thereby shortening the test process and improving test efficiency.

[0079] Figure 6 is a flow chart illustrating an image sensor testing method based on an example implementation of the disclosed technology.

[0080] Reference Figure 6 At S101, the test device 130 may apply a single temperature signal TT to the sampling pixel array 111. At S103, the temperature sensors 1131, 1132, ..., 113N may send temperature detection signals to the test device 130 through the sampling pixel groups G1, G2, ..., GN.

[0081] The sampled active pixels in the sampled pixel groups G1, G2, ... GN may be shielded from light during the test operation. At S105, the test device 130 may receive a temperature detection signal corresponding to the sampled pixel groups G1, G2, ... GN, an optical black signal from the sampled light-shielded pixel, and an active black signal from the sampled active pixel to determine a dark level correction value. In some example embodiments of the disclosed technology, a dark level correction value according to the operating temperature of the sampled pixel group may be calculated. A dark level correction value at a non-measurement temperature may be predicted based on the calculated dark level correction value.

[0082] At S107, the test device 130 may determine a correction coefficient according to a base value of an operating temperature that is added when a difference between the levels of an active black signal and an optical black signal of a sampling pixel can be compensated. In an example embodiment, a base value correction coefficient according to an operating temperature of a sampling pixel group may be calculated. A base value correction coefficient at a non-measurement temperature may be predicted based on the calculated base value correction coefficient.

[0083] The base correction coefficient may be determined based on a ratio of an active black signal to an optical black signal for the operating temperature of the sampled pixel. At S105 and S107, the determined and / or predicted dark level correction value and base correction coefficient for the operating temperature may be maintained in a lookup table. The disclosed technology may be implemented in some embodiments to provide a determined and / or predicted dark level correction value and base correction coefficient for each of the operating temperatures. The disclosed technology may be implemented in some embodiments to provide a processor including hardware and / or software that calculates a mathematical formula for obtaining a dark level correction value and a base correction coefficient for each temperature range.

[0084] Figure 7 An electronic device based on an example implementation of the disclosed technology is shown.

[0085] Reference Figure 7 , the electronic device 20 may include an image sensor 1000, an image signal processor (ISP) 2000, and a display unit 3000. The electronic device 20 may include a digital camera, a portable electronic device having a digital camera (e.g., a cellular phone, a smart phone, a tablet personal computer), etc. An image signal processor (ISP) is a processor used for image processing to improve the quality of an image captured by an image sensor and may perform image processing operations such as color correction, noise removal, etc.

[0086] The image sensor 1000 may include a CMOS image sensor. The image sensor 1000 may sense an object based on light incident through the lens 4000 by the control of the image signal processor 2000. The image sensor 1000 may output the generated image data to the image signal processor 2000. The image signal processor 20000 may digitize the image signal output from the image sensor 1000. The image signal processor 2000 may transmit the digital image signal to the display unit 3000.

[0087] The image sensor 1000 and the image signal processor 2000 may include a printed circuit board (PCB) such as a motherboard, an integrated circuit (IC), a system on chip (SoC), etc. In example embodiments, the image sensor 1000 and the image signal processor 2000 may be implemented as one package (e.g., a multi-chip package (MIP), a system-in-package (SIP), etc.). The image sensor 1000 may include a separate chip (e.g., a CMOS image sensor chip).

[0088] The calibration data can be obtained by referring to the calibration data when manufacturing the image sensor 1000. Figures 1 to 6 The test system and method described herein determine (extract). The processor is configured to calculate the determined correction data or the correction data may be stored in a storage device of the image signal processor 2000 to reflect the object as a digital signal.

[0089] Figure 8 An electronic device based on an example implementation of the disclosed technology is shown.

[0090] Reference Figure 8 , the electronic device 20 - 1 may include an image sensor 1000 and an ISP 2000 .

[0091] The image sensor 1000 may include a pixel array 1100 , a row driver 1200 , a correlated double sampler (CDS) 1300 , a digital-to-analog converter (ADC) 1400 , a timing generator 1500 , a ramp signal generator 1600 , a control register 1700 , and a buffer 1800 .

[0092] The pixel array 1100 may include an active region 117A, an optical black region 117B, and a dummy region 117C. A plurality of active pixels APX may be formed in the active region 117A. An optical black pixel OBPX may be formed in the optical black region 117B.

[0093] A selected active pixel APX among a plurality of active pixels APX may be connected to any one of a row line (not shown) and any one of a column line (not shown). The selected active pixel APX may generate an active signal corresponding to a wavelength of light. For example, each of the active pixels APX may convert optical image information into an electrical image signal to output the electrical image signal to the CDS 1300 through a column line. The active pixel APX may include an optical detection element (e.g., a photodiode, a pinned photodiode, a photogate, etc.).

[0094] Each of the active pixels APX may have Figure 4 The structure in is not limited to a specific structure.

[0095] The optical black pixels OBPX in the optical black pixel region 117B may shield incident light to generate an optical black signal having a dark level. Each of the optical black pixels OBPX may include an optical detection element.

[0096] In an example embodiment, the pixel array 1100 may include Figure 1 , Figure 2B and Figure 5 The sampling pixel array, temperature sensor 113 and temperature detector 1331 in.

[0097] The control register 1700 may generate at least one control signal for controlling operations of the timing generator 1500 , the ramp signal generator 1600 , and the buffer 1800 .

[0098] The row driver 1200 may drive the pixel array 1100 in units of rows. That is, the row driver 1200 may generate a row selection signal for selecting any one of the rows in the pixel array 1100.

[0099] Each active pixel APX may sense incident light to output an active signal to the CDS 1300. Each optical black pixel OBPX may output an optical black signal to the CDS 1300.

[0100] The CDS 1300 may perform correlated double sampling with respect to the received active signal and the optical black signal.

[0101] In an example embodiment, the CDS 1300 may hold and sample the voltage level of the received electrical image signal and the reference voltage level according to the provided clock signal. The CDS 1300 may then send an analog signal corresponding to the difference between the reference voltage level and the voltage level of the electrical image signal to the ADC 1400 .

[0102] The ADC 1400 may compare the ramp signal generated from the ramp signal generator 1600 with the correlated double sampling signal output from the CDS 1300 to output a plurality of comparison signals. The ADC 1400 may transmit count values ​​of the comparison signals in response to transition times of the clock signal to the buffer 1800.

[0103] The buffer 1800 may temporarily store the count value (ie, the digital active signal output from the ADC 1400). The buffer 1800 may sense, amplify, and output the digital active signal. The digital signal input into the buffer 1800 may include a dark current caused by the photoelectric conversion element PD.

[0104] The ISP 2000 may reflect the dark level correction value and the base correction coefficient on the digital image signal transmitted from the buffer 1800 of the image sensor 1000 to control the offset.

[0105] The ISP 2000 may include a processor 2010 , a memory 2020 , a temperature detector 2030 , and an interface circuit 2040 .

[0106] The processor 2010 may be configured to control the overall operation of the ISP 2000 .

[0107] The memory 2020 may include a one-time programmable (OTP) memory without being limited to a specific type.

[0108] The temperature detector 2030 may detect the operating temperature of the image sensor 1000 to determine a dark level correction value and a base correction coefficient according to the temperature. The temperature detector 2030 may be located outside the ISP 2000.

[0109] The interface circuit 2040 may provide a communication environment between the electronic device 20 - 1 and an external device.

[0110] In the example implementation, by referring to the above Figures 1 to 6 The correction data determined by the test system 10 discussed (eg, dark level correction values ​​and floor correction coefficients for each temperature range) may be stored in a lookup table (LuT) 2021 in the memory 2020 .

[0111] The processor 2010 may detect the operating temperature of the image sensor 1000 based on the temperature detection signal received from the temperature detector 2030. The processor 2010 may calculate correction data including a dark level correction value and a base correction coefficient on the basis of the temperature range based on the lookup table 2021. The processor 2010 may reflect the calculated correction data on the digital image signal output from the image sensor 1000 to control the offset. The processor 2010 may then output the controlled offset to an external device (e.g., a display) through the interface circuit 2040.

[0112] Processor 2010 can use by referring to Figures 1 to 6 The test system 10 discussed herein determines a correction data formula for each operating temperature. The processor 2010 may identify the operating temperature of the image sensor 1000 based on the temperature detection signal received from the temperature detector 2030. The processor 2010 may use a calculation formula to obtain correction data including a dark level correction value and a base correction coefficient corresponding to the current temperature. The processor 2010 may reflect the calculated correction data on the digital image signal output from the image sensor 1000 to adjust the offset. The processor 2010 may then output the adjusted offset to an external device through the interface circuit 2040.

[0113] In an example embodiment, when the pixel array 1100 may include Figure 1 , Figure 2B and Figure 5 When the pixel array 1100 includes the temperature sensor 1331, the processor 2010 may include a dark level correction value determination circuit 1333 and a base correction coefficient determination circuit 1335 to determine correction data based on the temperature on the basis of the sampled pixel group. In some implementations, when the pixel array 1100 includes the temperature sensor 1331, the temperature detector 2030 in the ISP 2000 may be omitted.

[0114] Fig. 9 An electronic device based on an example implementation of the disclosed technology is shown.

[0115] Reference Fig. 9 , the electronic device 5000 may include an image processor 5100 , a communication device 5200 , an audio processor 5300 , a display device 5400 , a buffer memory 5500 , a nonvolatile memory 5600 , a user interface 5700 , and a main processor 5800 .

[0116] The image processor 5100 may receive an optical signal through the lens 5110. The image sensor 5120 and the image signal processor 5130 in the image processor 5100 may generate image data representing an object based on the received optical signal. For example, the image sensor 5120 and the image signal processor 5130 may have the same Figure 7 and Figure 8 The image sensor and image signal processor have the same or similar functions.

[0117] The communication device 5200 may exchange signals with an external device through an antenna 5210. A transmitter / receiver (transceiver) 5220 and a modem 5230 in the communication device 5200 may process signals exchanged with the external device based on various wireless communication protocols or rules.

[0118] The audio processor 5300 may process a digital audio signal using the audio signal processor 5310. The audio processor 5300 may receive an audio signal through the microphone 5320 to digitally process the audio signal. The audio processor 5300 may regenerate the audio signal to output the regenerated audio signal through the speaker 5330.

[0119] The display device 5400 may receive data from an external device such as the main processor 5800. The display device 5400 may display an image through a display panel based on the received data.

[0120] The buffer memory 5500 may store data used for the operation of the electronic device 5000. The buffer memory 5500 may temporarily store data processed by or to be processed by the main processor 5800. For example, the buffer memory 5500 may include a volatile memory such as a static random access memory (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), etc., a nonvolatile memory such as a phase change RAM (PRAM), a magnetoresistive RAM (MRAM), a resistive RAM (ReRAM), a ferroelectric RAM (FRAM), etc.

[0121] The nonvolatile memory 5600 can store data regardless of the supply of power. The nonvolatile memory 5600 may include at least one of a flash memory, a PRAM, an MRAM, a ReRAM, a FRAM, etc. The nonvolatile memory 5600 may include a removable memory such as a secure digital (SD) card and / or an embedded memory such as an embedded multimedia card (eMMC).

[0122] The user interface 5700 may provide an interface for communication between a user and the electronic device 5000. For example, the user interface 5700 may include an input interface such as a keypad, a button, a touch screen, a touch pad, a gyroscope, a vibration sensor, an acceleration sensor, etc. The user interface 5700 may include an output interface such as a monitor, an LED light, etc.

[0123] The main processor 5800 may control the overall operation of the electronic device 5000. The main processor 5800 may perform calculations to operate the electronic device 5000. For example, the main processor 5800 may include at least one processor core such as a general-purpose processor, a dedicated processor, an application processor, and a microprocessor.

[0124] Only limited examples of implementations or embodiments of the disclosed technology are described or shown. Based on the contents disclosed and described in this patent document, changes and enhancements to the disclosed implementations or other embodiments are possible.

[0125] CROSS-REFERENCE TO RELATED APPLICATIONS

[0126] This patent document claims priority to and the benefit of Korean Application No. 10-2020-0187263, filed on December 30, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. An image sensor, comprising: an active pixel array, the active pixel array comprising a plurality of active pixels operable to convert incident light into pixel signals carrying image information in the incident light; a plurality of sampling pixel groups, the plurality of sampling pixel groups being located adjacent to the active pixel array but spatially separated from the active pixel array and having different heat dissipation characteristics than other sampling pixel groups; as well as a plurality of temperature sensors, the plurality of temperature sensors being respectively coupled to the sampling pixel groups to provide temperature measurements, Each of the plurality of sampling pixel groups includes a plurality of photoelectric conversion elements formed in a substrate, a light collection layer, and a heat dissipation layer arranged between the plurality of photoelectric conversion elements and the light collection layer, and wherein the heat dissipation layers of different sampling pixel groups have different thicknesses.

2. The image sensor according to claim 1, wherein: Each of the plurality of sampling pixel groups includes an optical black pixel configured to generate a dark current by blocking light from entering the optical black pixel and an active pixel configured to convert incident light into a pixel signal.

3. The image sensor according to claim 1, wherein: Each of the plurality of sampling pixel groups comprises: the substrate supporting the plurality of photoelectric conversion elements formed in the substrate; a grid pattern formed on the substrate along boundaries between adjacent photoelectric conversion elements; the heat dissipation layer, the heat dissipation layer being formed on the substrate and the grid pattern; a color filter formed on the heat dissipation layer; and The light collecting layer is formed on the color filter.

4. The image sensor according to claim 3, wherein: The heat dissipation layer includes an insulating layer.

5. The image sensor according to claim 4, wherein: The insulating layer includes SiO2.

6. The image sensor according to claim 3, wherein: The heat dissipation layer includes a low thermal conductivity material.

7. The image sensor according to claim 6, wherein: The low thermal conductivity material includes air gaps.

8. An image sensor testing system, the image sensor testing system comprising: an image sensor including a plurality of sampling pixel groups having heat dissipation characteristics different from other sampling pixel groups and a plurality of temperature sensors respectively coupled to the sampling pixel groups to generate temperature detection signals; a temperature detector that receives the temperature detection signals corresponding to the sampling pixel groups from the temperature sensors, respectively, to determine operating temperature information associated with the sampling pixel groups; as well as a test device that receives a dark current from the sampling pixel group to determine correction data to be used to correct the dark current, the correction data including a dark level correction value and a base correction coefficient for each temperature range, Each of the plurality of sampling pixel groups includes a plurality of photoelectric conversion elements formed in a substrate, a light collection layer, and a heat dissipation layer arranged between the plurality of photoelectric conversion elements and the light collection layer, and wherein the heat dissipation layers of different sampling pixel groups have different thicknesses.

9. The image sensor testing system according to claim 8, wherein: The testing device includes a test pattern generator that sends a single temperature signal to the image sensor to increase a temperature in the image sensor.

10. The image sensor testing system according to claim 8, wherein: The temperature detector is incorporated into the image sensor or the testing device.

11. The image sensor testing system according to claim 8, wherein: Each of the plurality of sampling pixel groups includes an optical black pixel and an active pixel, and the test device determines the correction data for each temperature range based on an optical black signal of the optical black pixel and an active black signal of the active pixel.

12. The image sensor testing system according to claim 8, wherein: The heat dissipation layer includes an insulating layer including SiO2.

13. The image sensor testing system according to claim 8, wherein: The heat dissipation layer includes air gaps.

14. A method for testing an image sensor, the method comprising the following steps: Providing an image sensor including a plurality of sampling pixel groups having different heat dissipation characteristics and a plurality of temperature sensors respectively coupled to the sampling pixel groups; providing a test device to receive operating temperature information including temperatures in the sampled pixel group in the test device; receiving a dark current from the sampling pixel group; as well as determining correction data to be used for correcting the dark current, wherein the correction data includes a dark level correction value and a base correction coefficient for each temperature range, Each of the plurality of sampling pixel groups includes a plurality of photoelectric conversion elements formed in a substrate, a light collection layer, and a heat dissipation layer arranged between the plurality of photoelectric conversion elements and the light collection layer, and wherein the heat dissipation layers of different sampling pixel groups have different thicknesses.

15. The image sensor testing method according to claim 14, wherein: Each of the plurality of sampling pixel groups includes an optical black pixel and an active pixel, and wherein receiving the dark current includes receiving an optical black signal of the optical black pixel and an active black signal of the active pixel.

16. The image sensor testing method according to claim 14, wherein: The testing device sends a single temperature signal to the image sensor to increase the temperature in the image sensor.

17. The image sensor testing method according to claim 14, wherein: The step of receiving the operating temperature information further includes: receiving a temperature detection signal from the temperature sensor by a temperature detector disposed inside or outside the image sensor to detect an operating temperature of the image sensor; and The operating temperature information is sent by the temperature detector to the testing equipment.

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